The present disclosure generally relates to systems and methods for acquiring data from a subject and, more particularly, to systems and methods for gathering and analyzing information about the subject's eye movements to determine or predict a state of the subject, including conditions such as traumatic brain injury (TBI) and other neurological injuries and diseases.
Brain injury can affect motor and cognitive function in the injured subject, and may increase the subject's vulnerability to a subsequent brain injury. When the brain injury is caused by trauma, such as an impact or piercing of the head, the subject is many times more likely to suffer a more severe injury the next time a similar trauma occurs. Concussion and other TBIs are currently at the forefront of sports medicine discussions, particularly for contact sports, because the risk to players is significant and the presence of a TBI cannot always be quickly diagnosed. For example, American football players are constantly at risk of a concussion, but often return to the game after a TBI because their visible symptoms were not cause for concern and a quick objective test is not available.
Another problem with diagnosing TBI is that most symptoms can be transient. Thus, with the passage of time it becomes more difficult to detect an injury, and medical examinations and accident investigations can be compromised. Early, quick, and objective detection of the physiological effects of TBI is needed.
The eye movements of people with neurological disease differ significantly from those of healthy people. The eyes in both populations do not stay perfectly still during visual fixation. Fixational eye movements and saccadic intrusions continuously change the position of the gaze. Microsaccades are rapid, small-magnitude involuntary saccades that occur several times each second during fixation; microsaccades counteract visual fading and generate strong neural transients in the early visual system. Microsaccades may also drive perceptual flips in binocular rivalry. Microsaccade rates and directions are moreover modulated by attention, and thus generate rich spatio-temporal dynamics. Further, fixational eye movements as a whole enhance fine spatial acuity. Abnormalities and intrusions in these eye movements can belie neurological impairments.
It would be beneficial to be able to detect TBI and differentially diagnose it from another neurological injury or disease in a non-invasive manner. The following disclosure provides one such differential diagnostic method.